The present invention concerns a process of removing metals from waste. One embodiment of the process specifically involves recovery of nickel and vanadium from scrubber waste.
Many industries produce waste which contains metals. Some of these metals are toxic, and therefore the waste containing them can be hazardous to store. One specific example is cogeneration plants which burn coal or coke to product steam and electricity. Such plants often include stack gas scrubber units which produce metal-containing waste. Scrubber units are also used in oil refineries and chemical plants.
Reducing the metal content of such waste would not only have environmental benefits, but could also be profitable, since metals such as nickel and vanadium have significant value.
Processes presently exist for removing metals from such waste using solvent extraction. However, waste treatment plants using solvent extraction processes tend to be relatively expensive. An improved process that could efficiently remove metals from scrubber waste, or at least significantly reduce their concentration, would have substantial economic and environmental benefits.